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Examples.First.md

Examples.First ​

First example: simple drive train.

The drive train consists of a motor inertia which is driven by a sine-wave motor torque. Via a gearbox the rotational energy is transmitted to a load inertia. Elasticity in the gearbox is modeled by a spring element. A linear damper is used to model the damping in the gearbox bearing.

In Dyad, support flanges are always present. Both torque source and ideal gear supports are explicitly connected to the fixed reference, matching the MSL variant with useSupport=true.

Note: In Dyad (where support is always present), this model is topologically identical to FirstGrounded. Both are provided for MSL parity.

Corresponds to Modelica.Mechanics.Rotational.Examples.First. StopTime=1.0, Interval=0.001.

Usage ​

RotationalComponents.Examples.First()

Behavior ​

julia
using RotationalComponents #hide
using ModelingToolkit #hide
@named sys = RotationalComponents.Examples.First() #hide
full_equations(sys) #hide
<< @example-block not executed in draft mode >>

Source ​

dyad
"""
First example: simple drive train.

The drive train consists of a motor inertia which is driven by a sine-wave
motor torque. Via a gearbox the rotational energy is transmitted to a load
inertia. Elasticity in the gearbox is modeled by a spring element. A linear
damper is used to model the damping in the gearbox bearing.

In Dyad, support flanges are always present. Both torque source and ideal gear
supports are explicitly connected to the fixed reference, matching the MSL
variant with useSupport=true.

Note: In Dyad (where support is always present), this model is topologically
identical to FirstGrounded. Both are provided for MSL parity.

Corresponds to Modelica.Mechanics.Rotational.Examples.First.
StopTime=1.0, Interval=0.001.
"""
example component First
  "Fixed mechanical ground."
  fixed = RotationalComponents.Components.Fixed() {}
  "Torque source driven by external sine signal (useSupport=true in MSL)."
  torque = RotationalComponents.Sources.TorqueSource() {}
  "Motor inertia, J=0.1 kg.m^2."
  inertia1 = RotationalComponents.Components.Inertia(J = 0.1) {}
  "Ideal gear with ratio=10 (useSupport=true in MSL)."
  ideal_gear = RotationalComponents.Components.IdealGear(ratio = 10) {}
  "Intermediate inertia after gearbox, J=2 kg.m^2."
  inertia2 = RotationalComponents.Components.Inertia(J = 2) {}
  "Torsional spring in gearbox, c=1e4 N.m/rad."
  spring = RotationalComponents.Components.Spring(c = 1e4) {}
  "Load inertia, J=2 kg.m^2."
  inertia3 = RotationalComponents.Components.Inertia(J = 2) {}
  "Bearing damper, d=10 N.m.s/rad."
  damper = RotationalComponents.Components.Damper(d = 10) {}
  "Sine torque signal, amplitude=10 N.m, frequency=5 Hz."
  sine = BlockComponents.Sources.Sine(amplitude = 10, frequency = 5) {}
relations
  initial inertia2.phi = 0
  initial inertia2.w = 0
  initial spring.phi_rel = 0
  initial inertia3.w = 0
  connect(sine.y, torque.tau)
  connect(torque.spline, inertia1.spline_a)
  connect(torque.support, fixed.spline)
  connect(inertia1.spline_b, ideal_gear.spline_a)
  connect(ideal_gear.spline_b, inertia2.spline_a)
  connect(ideal_gear.support, fixed.spline)
  connect(inertia2.spline_b, spring.spline_a, damper.spline_a)
  connect(spring.spline_b, inertia3.spline_a)
  connect(damper.spline_b, fixed.spline)
metadata {
  "Dyad": {
    "icons": {"default": "dyad://RotationalComponents/Example.svg"},
    "tests": {
      "case1": {
        "stop": 1,
        "expect": {"initial": {"inertia2.phi": 0, "inertia2.w": 0, "inertia3.w": 0}}
      }
    }
  }
}
end
Flattened Source
dyad
"""
First example: simple drive train.

The drive train consists of a motor inertia which is driven by a sine-wave
motor torque. Via a gearbox the rotational energy is transmitted to a load
inertia. Elasticity in the gearbox is modeled by a spring element. A linear
damper is used to model the damping in the gearbox bearing.

In Dyad, support flanges are always present. Both torque source and ideal gear
supports are explicitly connected to the fixed reference, matching the MSL
variant with useSupport=true.

Note: In Dyad (where support is always present), this model is topologically
identical to FirstGrounded. Both are provided for MSL parity.

Corresponds to Modelica.Mechanics.Rotational.Examples.First.
StopTime=1.0, Interval=0.001.
"""
example component First
  "Fixed mechanical ground."
  fixed = RotationalComponents.Components.Fixed() {}
  "Torque source driven by external sine signal (useSupport=true in MSL)."
  torque = RotationalComponents.Sources.TorqueSource() {}
  "Motor inertia, J=0.1 kg.m^2."
  inertia1 = RotationalComponents.Components.Inertia(J = 0.1) {}
  "Ideal gear with ratio=10 (useSupport=true in MSL)."
  ideal_gear = RotationalComponents.Components.IdealGear(ratio = 10) {}
  "Intermediate inertia after gearbox, J=2 kg.m^2."
  inertia2 = RotationalComponents.Components.Inertia(J = 2) {}
  "Torsional spring in gearbox, c=1e4 N.m/rad."
  spring = RotationalComponents.Components.Spring(c = 1e4) {}
  "Load inertia, J=2 kg.m^2."
  inertia3 = RotationalComponents.Components.Inertia(J = 2) {}
  "Bearing damper, d=10 N.m.s/rad."
  damper = RotationalComponents.Components.Damper(d = 10) {}
  "Sine torque signal, amplitude=10 N.m, frequency=5 Hz."
  sine = BlockComponents.Sources.Sine(amplitude = 10, frequency = 5) {}
relations
  initial inertia2.phi = 0
  initial inertia2.w = 0
  initial spring.phi_rel = 0
  initial inertia3.w = 0
  connect(sine.y, torque.tau)
  connect(torque.spline, inertia1.spline_a)
  connect(torque.support, fixed.spline)
  connect(inertia1.spline_b, ideal_gear.spline_a)
  connect(ideal_gear.spline_b, inertia2.spline_a)
  connect(ideal_gear.support, fixed.spline)
  connect(inertia2.spline_b, spring.spline_a, damper.spline_a)
  connect(spring.spline_b, inertia3.spline_a)
  connect(damper.spline_b, fixed.spline)
metadata {
  "Dyad": {
    "icons": {"default": "dyad://RotationalComponents/Example.svg"},
    "tests": {
      "case1": {
        "stop": 1,
        "expect": {"initial": {"inertia2.phi": 0, "inertia2.w": 0, "inertia3.w": 0}}
      }
    }
  }
}
end


Test Cases ​

julia
using RotationalComponents
using DyadInterface: TransientAnalysis, rebuild_sol, ODEAlg
using ModelingToolkit: toggle_namespacing, get_initial_conditions, @named
using CSV, DataFrames, Plots

snapshotsdir = joinpath(dirname(dirname(pathof(RotationalComponents))), "test", "snapshots")
<< @setup-block not executed in draft mode >>

Test Case case1 ​

julia
@named model_case1 = RotationalComponents.Examples.First()
model_case1 = toggle_namespacing(model_case1, false)

model_case1 = toggle_namespacing(model_case1, true)
result_case1 = TransientAnalysis(; model = model_case1, alg = ODEAlg.Auto(), start = 0e+0, stop = 1e+0, abstol=1e-6, reltol=1e-6)
sol_case1 = rebuild_sol(result_case1)
<< @setup-block not executed in draft mode >>

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